Control apparatus



Peb. 25,1941.

R. L. WILS'ON CONTROL A PPARATUS Filed Feb. 12,' 1940 7 Sheets-Sheet 1 "f 4mm? ggf ff F59 530 4A f/ f 'lHllllllIl .Feb- 25, 1941- R. wlL'soN A 2.232.152

connor. APPARATUS Filed Feb. 12, 1940 7' Sheets-Sheet 2 IFel. 25, 1941.

CONTROL. APPARATUS R. L. wiLsoN 2,232,752

7 Sheets-Sheet 3 Filed Feb. 1 2, 1940 Feb. 25, 1941. R. WILSON 2232,752

CONTROL APPARATUS v Filed Feb. 12, 1940 '7 Sheets-Sheet 4 f .K f 50% Feb. 25, 1941. R; wlLsoN CONTROL APPARATUS '7 Sheets-Sheet 5 Filed Feb. l2, 1940 Feb. 25, 1941'.

R. L. fwlLsN CONTROL APPARATUS Filed Feb. l2, 194C) 7 sheets-sheet s Feb. 2 5, 1941. R. L. WILSON 2,232,752

co'NTRoL APPARATUS Filed Feb. 12, 1940 7 Sheets-Sheet '7 www,

Patented Feb. 25, 1941 UNITED STATES PATENT OFFICE CONTROL APPARATUS Rosser L. Wilson, Mahwah, N. J., asslgnor to The American Brake Shoe and Foundry Company, Wilmington, Del., a corporation of Delaware This application is led in place of and constitutes a continuation in part of my allowed application Serial No. 213,103, filed June 10, 1938.

This invention relates to control apparatus and particularly to apparatus for controlling or otherwise affecting the braking of railway equipment and the like.

In the normal operation of railway equipment it is believed 4that there is no slippage at .the 3@ points of contact of the wheels of the equipment with the rails and that the wheels roll along .the

rails. During a braking operation on such equipment the retarding forces eiective on the wheels react at the rails to slow down the rolling move- 115 ment of the wheels and so long as the adhesion between each wheel and rail on which it rolls exceeds the retarding force effective on the wheel,

the wheel is retarded without slippage at the contact thereof with the rail. It has .been observed gn however, where the retarding force in a braking operation exceeds ,the force of adhesion between a wheel and the rail on which it rolls, that the wheel slips on .the rail and is thereafter retarded at a rate exceeding that at which it would have g5 been retarded had not .the slippage occurred and as a result the wheel comes to rest prematurely and thereafter slides along .the rail.

There are many factors which may cause .the

retarding force effective on a Wheel in a braking s@ operation to exceed the adhesion between the wheel and the rail on which it rolls. For example, the braking means of railway equipment is so arranged that the friction between the elements Ithereof is less than what has come to be 35 generally accepted as the usual value of the ad- 'heslon or friction between :the wheel or wheels decelerated by operation of the braking means and the rail on which such wheel or wheels rolls or roll. There may be, however, an unpredict- ,m able increase in. the friction Ibetween the elements of the braking means or the friction between the wheel or wheels and rail or rails may unaccountably drop below what has come to be generally accepted as the value of such friction,

and of course there may be a combination of such variations. If such vari-ation occurs in a braking operation it is quite likely that the Wheel or wheels affected thereby will slip on, rather than roll on, the rail or rails whereupon, as prem viously explained, the Wheel yor wheels may prematurely stop rolling and thereafter slide along the rail or rails. Such sliding of the wheels along the rails may impair the braking operation in which it occurs and may result in serious damage 55 such as producing so-called ats on the wheels.

It will Ibe understood .that wheel sliding may be occasioned in a wide variety of ways but that however occasioned it is objectionable.

Thus an important object of the present invention is to prevent ina novel manner, in the 5 course of a braking operation, sliding of a wheel of railway equipment along the rail on which the wheel rolls. l I Further and related objects are t0 detect slippage, in a braking operation, of a wheel on the rail on which it normally rolls before the wheel prematurely stops rolling and begins to slide along the rail land to render the braking means operative to effect deceleration of the wheel ineffective, or .to reduce the retarding force estabt5 lished by operation of such means, until normal rolling of the wheel affected by the retarding force has been reestablished; to again render .the braking means eective afternormal rolling of v the Wheels has been reestablished if the means operative to bring about operation of the braking means, which were effecting retardation of the wheels when slippage thereof on the rails occurred, are still being maintained operative at the time the normal rolling of the wheels is reestablished.

It has vbeen observed in 'braking operations on railway equipment that, when Aa wheel slips on the rail on which it normally rolls and .prematurely stops rolling and thereupon slides along the rail, the wheel, insofar as its rotative movement is concerned, decelerates rapidly after the slippage occurs and quickly stops rolling to thereupon st-art to slide and also that Where lseveral wheels on different axles substantially simultaneously or simultaneously slip on the rail or rails on which .they normally roll the wheels usually decelerate, insofar as rotative movement thereof is concerned, at different rates and consequently stop rolling and start to slide at diierent times.

Such lack of uniformity in the slowing down of the wheels is probably due .to variations in the conditions at .the various wheels. These variations in lthe conditions may be due to diife'rences in the loads on the various wheels on diierent axles, differences in the retarding forces affecting the respective wheels on different axles, or the like. In any event, however, where lseveral wheels on different axles slip on .the rail or rails, a variation in therates of rotation of the various w-heels usually arises before any wheel prematurely stops rolling and starts to slide along Ia rail. The present invention is predicated upon this observation, which is to say, it is another important object of the present invention to effect a control operation in order that a condition of wheel sliding -will be prevented in event a wheel slips onI the rail on which it normally rolls and thereafter slows down more rapidly insofar as its rotative movement is concerned, than another associated wheel in the course of a braking operation.

Still another object of this invention is to operate elements at speeds respectively proportionate to the rates of rotation ofat least two wheels on a railway car or the like that are decelerated by different or independent braking means and to effect a control operation upon a predetermined variationin the rates of rotation of said elements relative to each other as, for example, where there is such a variation in rates of rotation in the course of a braking operation, to release the braking means effective on the wheel or wheels with which the element or elements rotating at the lower rates are associated, or to reduce the retarding force established by opera.-A

tion of such means, whereby sliding of the wheel or wheels, decelerated by such braking means, along the rail or rails on which it or they normally roll may be prevented.

It is recognized that the rates of movement of the various movable elements, such as the rates of rotation of the various wheels on a railway car or the like that are decelerated by independent braking means may not always be the same. For example, as applied to railway equipment, there may he a difference in the diameters of such Wheels at the lines of contact thereof with the rail or rails which will, of course, cause the wheels to rotate at different rates in normal operation as well as during a braking operation. Thus elements operated at rates proportionate to the rates oi.' rotation of wheels that are deceleratedl by independent braking means may not always operate at the same rate either in normal operation or during a braking operation. Where such elements are employed to effect a control operation, such as the release of the braking means when the elements operate at different rates during a braking operation, there may be instances where the elements will be operating at different rates even during a braking operation and yet there will be no need of eecting the control operation because there will not be present an abnormal condition which the control operation is to overcome. y

Hence still another object of the present invention is to employ elements, each operative at a rate proportionate to the rate of rotation of a wheel on railway equipment, to effect a control operation, such as the release of the braking means, only when the elements operate at differences in rates predetermined to be indicative of abnormal conditions.

Since in many instances. as in the case of railway equipment, elements operated at rates proportionate to the rates of rotation of wheels as aforesaid may operate at different rates, as in the course of a braking operation, under conditions in which it will not be desirable to effect a control operation, such as the selective releasing of the independent braking means operative to decelerate the respective wheels or sets thereof, it is advantageous to interpose devices entailing a time factor in their operation intermediate the elements and the means under control thereof so that a time factor will enter into the determination of the existence of an abnormal condition and so to do constitutes still another object of the present invention.

More specifically, an object oi this invention is Ato bring about successive or alternate periods of operation of slow-to-release relays and when the intervals between such periods of operation are reduced in a predetermined amount to effect simultaneous operation instead of alternate operation, and an object ancillary to the foregoing is to render operative means under control of the relays only upon simultaneous operation of such slow-to-release relays.

Further objects are to employ elements, such as may be operated at rates proportionate to the rates of rotation of the wheels of railway or like equipment that are decelerated by independent braking means, to alternately render operative devices which may be brought into simultaneous operation and thereby bring about a control operation or the like and to maintain operative for a predetermined time whatever means are rendered effective to bring about the control operation whenever the interval intermediate alternate periods of operation of alternately operable devices is so reduced that the intermediate interval is eliminated; and to effect concurrent operation of normally alternately operable devices to bring about a control 0peration or the like and to maintain operative for a predetermined time whatever means are effective to bring about the control operation only under predetermined conditions.

In an arrangement where devices are alternately set in operation in such a way that under predetermined conditions the interval between i the alternate operations is so reduced that the operations become simultaneous rather than al ternate, it will berecognized that there will be instances where such simultaneous operation may be relatively brief. If such an arrangement is utilized to effect a control operation, such as the release of the braking means 4employed to decelerate a particular Wheel orY set of wheels of railway equipment, conditions might arise where the aforesaid relatively brief simultaneous operations in rather rapid succession might be caused to repeatedly occur for relatively short periods, and this would cause the control or other operation brought about by such simultaneous operations to be initiated and interrupted, successively, as where the control operation is the release of the braking means of railway equipment operative to slow down a particular wheel or set thereof, it might bring about alternate release and application of such braking means in rather rapid succession. Furthermore, conditions might arise where the aforesaid simultaneous operation might be brief but should nevertheless effect a relatively prolonged control operation such as relatively prolonged release of the braking means.

Hence, still another object of the present invention is to associate with alternately operable devices, which may be brought into simultaneous operation, an arrangement whereby the simultaneous operation of the devices will be caused to effect a predetermined operation even though the simultaneous operation may be relatively brief, and an object ancillary to the foregoing is to employ timed apparatus in association with alternately operable devices that may be brought into simultaneous operations so that upon simultaneous operation of the devices a predetermined operation may be effected for at least a predetermined time even though a period of simultaneous operation of the normally alternately operative devices may be relatively brief.

' If slippage of a wheel or set thereof, such as wheels mounted at oppositel ends of an axle, on the rail or rails on which it or they normally rolls or roll occurs during a braking operation and such slippage is such as might result 1n wheel sliding, and thereupon the braking means are rendered ineffective or the retarding force established by operation of such means is reduced, the wheel. or a set thereof. will resume normal rolling rather than slip on, or slide along, the rail or rails, and when such rolling is resumed the braking means may be again rendered effective. Hence among the objects of this invention are to not only render the braking means operative to decelerate a particular wheel, or a particular set of wheels, ineffective, or to reduce the retarding force established by operation thereof, when a wheel or set thereof slips on the rail or rails in the course of a braking operation in such a way that wheel sliding might result, but to render the braking meanswflective, if the means operative to bring about the braking operation are still operating, as soon as the wheel or wheels resumes normal rolling along the rail or rails, and to render the braking means eective, if the means operative to bring about the braking operation are still operating, after a predetermined period of time during which'lsuch braking means have been rendered ineffective, or the retarding force established by operation of the braking means is reduced, by reason of a wheel or set thereof slipping on the rail or rails in the course of a braking operation, provided the wheel or wheels is or are again normally rolling on the rail or rails upon the -elapse of such period of time.

The safety factor must be considered in any apparatus pertaining to the braking means of railway equipment and obviously any means which effects release of the braking means, or which reduces theretarding forces established by operation thereof, must be of such a nature that the braking means will not be permanently or improperly rendered ineffective or reduced in effectiveness, and hence yet another object of this invention is to so arrange the apparatus for effecting release of the braking means, or for reducing the retarding forces established by operation thereof, that the braking means will be released, or reduced in effectiveness, only under predetermined abnormal conditions, and an ancillary object is to so control the apparatus that the braking means will be released, or reduced 'in eectiveness, for onlya lpredetermined period of time.

A still further object somewhat related to the immediately foregoing objects is to so arrange the apparatus for effecting releaseof the braking means of railway equipment, or for reducing the retarding force established by operation of such means, that the apparatus will be rendered inoperative until manually again rendered operative in event the apparatus should fail to operate in the manner intended.

Still other objects of the invention are to indi- Y nately energizable electrically-operated devices which may be rendered simultaneously operative under predetermined conditions to control the ilow of current through a circuit other than the energizing circuit of such devices; to enable my novel control means to be vmaintained ineifective until initiation and prevalence of an operation to be controlled; to employ e; plurality of detecting arrangements and thereby insure accurate and positive operation oi my novel control means; to enable adjustment of my novel control means and thereby provide for variation in the sensitiveness thereof; to employ a series circuit and to effect a' predetermined operation only upon closure of such circuit; to employ a novel switch for regulating operation of slow-torelease relays or other devices embodying a time factor in their operation; to effect simultaneous operation of slow-to-release relays orthe like only upon predetermined relative movement between elements of means for generating an electric motive force; to move elements of means for generating. an electromotive force relative to each only upon predetermined conditions; to provide a novel switch for controlling flow of electric current through a circuit in which said switch is included; and to provide a novel control apparatus of simple and economical construction and positive and eflicient operation and which will withstand severe service without requiring constant attention and adjustment.

An additional object 'is to affect the braking of railway equipment or the like in a manner other than by releasing'the brakes or reducing the braking pressure, as for example'by supplying sand or the like to the rails in proximity to the Wheels when a predetermined tendency toward a wheel sliding condition is exhibited. In the present instance, the sanding apparatus is responsive to the means which detects a predetermined dierence in the relative rotative speeds of different wheels or the like and it may be used in conjunction with means that control the braking apparatus. If resort is had to such a conjoint arrangement, the 'apparatus is preferably so arranged that the control of the sand# ing apparatus is more sensitive to predetermined variations in the relative rotative speeds of different wheels or the like than is the control for the operation of the braking means, Hence when a predetermined variation in relative rotative speeds of the wheels is experienced, the rails are sanded ahead of the wheels to thereby increase the coefficient of adhesion between the wheels and the rails, and if this operation is successful in establishing normal rolling of the wheels, the brake pressure control means is not called into operation. Stated more broadly, it is an object of the invention to render the control v apparatus responsive to variations in rotative speeds of the wheels or the'like for effecting different control operations for different selected degrees of such variation during a braking operation.

Another object is to automatically sand the rails ahead o f the driving wheels of a locomotive or the like whenever a predetermined tendency toward skidding of any of these wheels arises during speeding up or starting thereof. It has been observed that such sanding of the rails greatly reduces and often eliminates the likelihood that one wheel will speed up appreciably more rapidly than another wheel under the above conditions. Preferably the sanding control apparatus is designed to function both during acceleration of the locomotive or other vehicle and upon deceleration thereof during a. braking operation; and hence my invention can be said to be applicable to prevent any predetermined variation in rotative speeds oi' the Whee on railway equipment or the like.

Still another object is to detect a variation from normal rolling condition of a wheel that has been braked, and to do this in a manner other than by comparing its rate of rotation with that of another wheel that has been braked, and more specifically to compare the rotative speed of a braked wheel with that of an unbraked element which is rotated at a speed proportionate to the linear speed of the vehicle or the like.

While in the foregoing discussion and in the following detailed description I refer to controlling the braking means of railway equipment, it is to be understood that my invention is not limited to control of the braking means of railway equipment for it can be employed to control braking means of other equipment on which slippage of a wheel thereof on the surface on which it normally rolls may occur, and furthermore the fundamentals underlying this invention may be employed to control a wide variety of operations in addition to braking operations. It is, therefore, to be understood that the foregoing discussion and following detailed description pertain to preferred embodiments of my invention and hence such discussion and description are not to be taken as a limitation of the invention.

Selected embodiments of my novel invention are illustrated in the accompanying drawings wherein Fig. 1 is a diagrammatic viewoi one embodiment of my invention associated with a pair of wheels such as are provided at one side oi' a truck on railway equipment;

Fig. 2 is a vertical sectional view of a switching means employed in the embodiment of my invention illustrated in Fig. 1; l

Fig. 3 is a transverse sectional view taken substantially on the line 3-3 on Fig. 2;

Fig. 4 is a sectional detail view taken substantially on the line 4-4 on Fig. 2;

Fig. 5 is a view, similar to Fig. 1, showing another form of my invention;

Fig. 6 is a diagrammatic view of a modification of the form of the invention shown in Fig. 5;

Fig. 7 is a diagrammatic view of a still further modified form of the invention shown in Fig. 5;

Figs. 8 and 9 are diagrammatic views of other forms of my invention;

Fig. 10 is a diagrammatic view, partly in elevation and partly in section, of a modified form of switch that may be employed;

Figs. 11, l2 and 13 are still further diagrammatic views of still other forms of my invention;

Fig. 13A is a diagrammatic view of still another form of switch that may be employed;

Fig. 14 is a diagrammatic view of an arrangement providing a common control for a plurality of control devices such as that to which this invention pertains;

Fig. 14A is a diagrammatic view of a yet further modifled form of my invention;

Fig. 15 is an elevational view of a conventional rail sanding apparatus as employed on a. railway vehicle such as a locomotive having three sets of driving wheels;

Fig. 16 is a partially schematic view of a modication of my invention for effecting operations such as sanding of the rails and brake releasing sheaves upon the occurrence ot an abnormal condition at the wheels;

Fig. 17 is an elevational view of a modified form of reversing switch for controlling the sanding apparatus shown inFig. 15; and

Fig. 18 is an elevational view of a further modification in which my novel switching means is associated with both a braked wheel and an unbraked wheel.

In the embodiment of my invention shown in Figs. 1 to 4, there is a. switch B which includes a. pair of rotors Il and il respectively fast to shafts I1 and Il journaled in suitable bearings in the rswitch housing il. A gear 20 fast on the shaft i1 meshes with a gear 2| fast on the shaft 22 which is also journaled in suitable bearings in the housing il, the gears 20 and 2 having a oneto-one ratio. The shaft 22 extends exteriorly of the housing I8 and one end oi' a nexible shaft 23 is connected to this end of this shaft, the other end of the flexible shaft being connected to a gear 24 that meshes with a gear 25 connected to a movable element such as the wheel FW for rotation therewith. In the present instance the gears 24 and 25 have a one-to-one ratio but this ratio may be varied as desired. Furthermore, the ilexible shaft 23 could be connected to the wheel to derive motion therefrom in other ways, is so desired, as by being directly connected to the axle to which the wheel might be fast. The shaft il also extends exteriorly of the housing and one end of a flexible shaft 26 is connected to this end of this shaft, the other end of this flexible shaft being connected to a gear 2l that meshes with a. gear 28 connected to a. second relatively movable element such as the wheel RW for `rotation therewith, this connection ot the shaft I8 to the Wheel RW being similar to connection of the shaft I1 to the Vwheel RW.

The wheels RW and FW as illustrated are to be mounted at one side of a truck (not shown) of railway equipment for movement along the rail T. These wheels are adapted to be slowed -down by the usual brake apparatus (not shown) provided on railway equipment, which apparatus includes the brake cylinder C to which a fluid under'pressure may be supplied through the pipe P. The brake apparatus is not illustrated inasmuch as the particular construction thereof forms no part of my invention which, in the illustrated forms, pertains to controlling the brake apparatus rather than to such apparatus per se. The relation of my invention to the brake apparatus is apparent from the illustration of my novel control means in association with the brake cylinder C to which huid under pressure is supplied when the wheels FW and RW are to be slowed down.

In the present instance my novel apparatus is employed to control operation of a. solenoidoperated check valve 29 and a solenoid-operated vent valve 20, each of which valves is positioned in the pipe P.

A conductor I2 connects one end of the winding 2| of the solenoid of the valve 29 to one end of the winding 22 of the solenoid of the valve 30. Another conductor 24 leads from the other end of the winding 3i to a source of current such as the battery B. Still another conductor 35 leads from this source ot current to a`contact I8 of the slow-to-release relay SRI, said contact 26 being engaged by the amature 31 of this relay during operation ot the relay. A further conductor Il leads from the armature 21 to a corntact 38 ot the slow-to-release relay SR2. this nected in series so that energization of the wind-- ings 3| and 33 is effected, to thereby operate the valves 29 andv 36, only when both the armatures 31 and 40 are engaging the contacts 36 and 39, this occurring only when the relays SRI and SR2 are operative simultaneously.

A conductor 42 leads from a source of current such as the battery BI to a terminal 43. Another conductor 44 leads from the terminal 43 to one end of the winding 45 of the relay SR2 and afconductor 46 leads from the terminal 43 to one end of the winding 41 of the relay SRI. Still another conductor y 46 leads from the source of current BI to ,a terminal 49, Fig. 2, ln the switch S. A further conductor D leads from the end of the winding 41 opposite that -to which the lconductor 46 is connected to a terminal 5Iin the switch S. Yet another conductor 52 leads fromthe end of the winding 45 opposit@ that to which the conductor u 1s connected to a terminal 53 in the switch S.

A conductor ring 54 is mounted on the rotor' I6 and a pair of conductor rings 55 and 56 is mounted in spaced relation on the rotor I5. The rotors I5 and I6 are preferably made of insulating material and hence the conductor rings 55 and 56 are insulated one from the other. A spring contact 51 mounted on the terminal 49 bears on the conductor ring 54 while spring contacts 58 and 56, respectively mounted on the terminals 5I and 53, respectively bear on the conductor rings 56 and 55. A pair of contact strips 66 and 6I is mounted -in the periphery of the rotor' I5 in diagrammatically opposite positions. 'I'hese strips (see Fig, 3) each preferably extend over one-quarter of the periphery of the rotor vso that the spacing between adjacent ends thereof is y ninety degrees and the extent oi each strip the contact strips 60 and,6I.

over the periphery of the rotor is ninety degrees. A conductor 62 (Fig. 4) interconnects the con tact strip 60 with the conductor ring 56 while a conductor 63 connects the contact strip 6I with the conductor ring 55. A spring finger 64 is mounted in the rotor I6 in electrical connection with the conductor ring 54 and extends over that part of the periphery of the rotor I5 on which the contact strips 60 and 6I are provided so that if the rotors I5 and I6 move relative to each other the spring finger 64 alternately engages Thus, these contact strips serve as a commutator while the spring finger 64 serves as a brush.

When the spring finger or brush 64 engages the contact strip 60, circuit is established from the source of current BI through conductor 48, spring contact 51, conductor ring 54, brush 64, contact strip 66, conductor 62, conductor ring 56, spring contact 56, conductor 50, through winding 41 and conductors 46l and 42 back to the source of current BI whereupon the slow-to-release relay SRI is energized. When, however, brush 64 engages the contact strip 6I circuit `is established from the source of current BI through conductor 46, spring contact 51, conductor ring 54, brush 64, contact strip 6I, conductor 63, conductor ring 55, spring contact 59, conductor 52, through winding 45 back to the source of current Ywheels.

BI through conductors 44 and 42 whereupon the slowvto-release relay SR2 is energized.

It will -be noted that the rotor I5 is connected through shaft I1, gears 20 and 2|, shaft 2,2, flexible shaft 23 and gears 24 and 25 to the wheel FW to rotate therewith and in the same direction and also that the rotor I6 is connected through shaft.

however, that the rotors could be caused to rotate at greater or less speeds or ratesthan the wheels, it only being important that the rates of rotation of the rotors be proportionate to the rates of rotation of the wheels.

When the rotors I5 and I6 both rotate at the same rate there is no relative. movement therebetween and the brush 64 rests on one or the other of the contact strips 66 and 6I or in a space betweenadjacentendsofthese strips, such spaces being, of sumcient width and the brush being sui'ciently narrow that the brush cannot engage both contact strips at the same time. Of course, whenever the brush 64 engages one or the other of the contact strips 60 or 6I, either the slow-torelease relay SRI or the slow-to-release relay SR2 is energized.

In the normal operation of railway equipment it is believed that there is no slippage at the points of contact of the wheels with the rails and the wheels roll along the rails. During a bralking with the rail. However, when the retarding force in a braking operation exceeds the adhesion between a wheel and the rail on which it normally rolls, the Wheel slips on the rail and is thereafter retarded at a rate exceeding that at .which it would have been retarded had not the slippage occurred, and as a result the wheel comes to rest prematurely and thereafter slides along the rail.

Thus, where either the rotor- I5 or I6 is connected to a Wheel which is retarded in the manner just described and the other rotor is connected to a'wheel which continues to roll on the rail, it is apparent that the rotor connected to the wheel which is so retarded will move relative to the other rotor in relatively rapid manner whereupon the contactor or brush 64 will engage the contact strips 90 and 9| in rapid succession. The rapidity with which the brush 64 so successively engages the contact strips 6I) and 6I is directly proportionate to the magnitude of the difference in the rates of rotation of the The magnitude of such diierence is relatively great when only one of the Wheels slips on the rail whilethe other continues to roll on the rail. However, it has been observed, where several wheels slip on the rails at the same time, that the wheels do not slow down uniformly, this probably vbeing due to varying conditions at the several wheels. Hence, where both the Wheels to which the rotors I5 and I8 are respectively connected slip on the rail, it is very unlikely that they will slow down uniformly and hence even in this condition there will be relative movement between the rotors I5 and I6 and the brush 84 will successively engage the contact strips 60 and 6I.

As explained heretofore, the contact strips 60 and 6I and the contact brush 64 are so arranged in circuit with the slow-to-release relays SRI and SR2 that when the lbrush 64 engages the contact strip or conductive segment 60 the relay SRI is energized, and when the brush B4 engages the strip 6I the relay SR2 is energized. Each of these relays is maintained energized so long as the brush @il remains in engagement with the contact strip in circuit with the particular relay and when, for example, the relay SRI is energized it attracts its armature 3l which thereupon engages the contact 36. Likewise when relay SR2 is energized it attracts its armature 40 which thereupon engages the contact 39. Furthermore, each of these relays, being a slow-to-release relay, remains operative after circuit thereto is broken, that is to say, for a predetermined time after circuit to the relay is broken its armature remains in engagement with the contact engaged by the armature upon energization of the relay, this being an inherent characteristic of a slow-to-release relay.

Hence, when the brush 6d successively engages the contact strips 60 and (il in such a way that one contact strip is disengaged and the other' strip is engaged and the relay in circuit with the second of the strips so engaged is energized in a period of time less than the predetermined time, the relay in circuit with the rst of said strips remains operative after circuit thereto is broken, by disengagement of the brush iid from the contact strip in circuit therewith, then both the relays SRI and SR2 are simultaneously operative. When this occurs both the armatures M and 31 are engaged with their cooperating contacts 39 and 36 and circuit is closed through the windings 3i and :i3 whereupon a control operation, such as release of the braking means effecting retardation or slowing down of the wheels, is effected, as will be more fully explained presently.

1t" is recognized that by reason of conditions encountered in the actual use of railway equipment there will be differences in the rates of rotation of wheels even when all the wheels are nor.. mally rolling along the rails. Such differences in rates of rotation may be due to differences in the diameters of the wheels at the lines of contact thereof with the rails. In fact, there may Ibe variations in the diameter of a single wheel at the line of contact thereof with the rail as the wheel rolls along the rail due to movement of the wheel in an axial direction. Since such conditions will exist, it is apparent that all differences in rates of rotationn between wheels, to which rotors as I5 and I6 are respectively connected, should -not cause these rotors to so rotate relative to each other that a control operation will be brought about. A control operation is not required unless an abnormal condition exists. To avoid a control operation unless an abnormal condition exists, provision is made to care for an extreme condition in actual operation, that is, a condition quite unlikely to be encountered, and the apparatus is so arranged that a control operation will not be effected under such extreme condition. In selecting such an extreme condition, one is chosen that will bracket other similar conditions and improper or undesired effecting of a control operation is therefore avoided. l

An example of such an extreme condition is where railway equipment is operating at a speed of one hundred twenty miles per hour and the difference in diameters of the wheels to which the rotors IB and I8 are connected is one inch at the lines of contact of such wheels with the rail or rails on which they normally roll as, for example, where the diameter of one wheel at the line of contact thereof with the rail is thirty-two inches and the diameter of the other wheel at the line of contact thereof with the rail is thirty-three inches. If a condition such as this prevailed the rotors I5 and I6 would rotate relative to each other even in normal operation and in the absence of slippage on the rail for there would be a difference in rotation therebetween of .634 revo lution per second.

As explained above, each of the contact strips Eiland 8i extends over one-fourth of the circumference of the rotor I5 so that there is a ninety degree interval intermediate adjacent ends of the strips as well as a ninety degree extent of the strips. Thus, under the foregoing conditions where there is a difference of .634 revolution per second in the rotation of the rotors I5 and I6 it will require .394 second for the brush 64 to ytravel from the end of one contact strip 5I) or tl to the adjacent end of the other contact strip. Hence if the slow-to-release relays are timed to remain operative, after circuit thereto is broken, for less than .394 second, the armatures 31 and it will not be simultaneously engaged with their cooperating contacts 3E and 39 under the extreme condition mentioned above which is an operating speed of one hundred twenty miles per hour and a difference in the diameters of the wheels at the lines of contact with the rail of one inch.

It is, however, advantageous to aflord a safety factor. Hence the slow-to-release relays may be timed to remain operative after circuit thereto is broken for approximately v.242 second. In this circumstance, in order for the armatures 31 and iii to be simultaneously engaged with their cooperating contacts it is necessary for there to be such relative rotation between the rotors I5 and i8 that the brush El will move from engagement with one of the contact strips 60 or 6I into engagement with the other of the contact strips in .242 second or less. It will be apparent that this is well beyond the time required for such successive engagement in the extreme condition described above which means that a control operation will `not be brought about under normal operating conditions.`

However, where slippage occurs between a wheel. to which one of the rotors I5 or IE is connected, and the rail on which the wheel rolls, and the other wheel does not slip, or even if there is slippage between both wheels to which the rotors are respectively connected, and the rail or rails on which such` wheels normally roll, there will be appreciable relative rotation between the rotors I5 or I8. Furthermore, once a wheel slips on the rail it thereafter, so far as its rotative movement is concerned, slows down rapidly and therefore almost or actually simultaneously with wheel slippage relative rotation between the rotors I5 and I6 is set up. Hence as soon as slippage occurs the brush 64 starts moving rapidly from engagement with one contact strip 60 or BI into engagement with the other of the contact strips. Moreover as soon as the time required forthe brush 94 to move from one contact strip to the other is equal to or less than .242 second, both the armatures 3l and 40 will be engaged with their cooperating contacts 39 and 39 whereupon circuit will be closed to the windings 3| and 33 to eiiect a control operation. Since slippage causes relatively great relative rotation between the rotors I5 and I9, the brush 94 will move from one contact strip to the other in .242 second or less practically simultaneously with 'the initiationy of wheel slippage.

While itis necessary that simultaneous engagement of the armatures 31 and 6I with their cooperating contacts is to be avoided in normal operation, it is desirable to establish this simultaneous cooperation promptly under abnormal conditions, as when slippage occurs, and to illustrate the promptitude with which this would be brought about under abnormal conditions it is possible to effect simultaneous closing of the switches, of which the armatures 31 and, 49 are a part, byv only having slightly more than ninety degrees of relative rotation between the rotors I6 and I6 for the brush 84 may be near the end of one contact strip `atthe time rapid relative rotation between the rotors I5 and I9 is initiated and thus the brush need only move slightly more l are a part, when an abnormal condition arises as,.-

for example, in event of wheel slippage in the course of a braking operation, if the relays SRI and SR2 have a release time of approximately .242 second and the diameter of both the wheels FW and RW at the lines of contact thereof with the rails is approximately thirty-three inches, (in this circumstance there will be no relative rotation between the rotors I5 and I9 in normal operation) a difference in the rates of rotation of the wheels equivalent to approximately six miles per hour will cause the brush 64 to move from association with one contact strip or 9| into engagement with the other contact vstrip in approximately .242 second and in proportionately less time as the difference in the rates oi' rotation increases. s

Since it is probable that the rotors I5 and I6 will be rotating relative to' each other even in normal operation, a further example of the operation of my novel apparatus, with particular reference to the extreme condition explained above, is now set forth. In such an extreme condition, entailing the connection of the rotors I5 and I9 respectively to wheels having an inch difference in diameter, that is, where one wheel is approximately thirty-two inches in diameter at the line of contact thereof with the rail and the other wheel ls approximately thirty-three inches in diameter at the line of contact thereof with the rail, there will normally be, in the absence of wheel slippage on the rail, a diierence of approximately .634 revolution per second in the rates of rotation of the wheels at one hundred twenty miles per hour. 'I'his is equivalent to a speed of approximately three and three-quarters miles per h our at the circumference of a thirtythree inch wheel. Now if, in such circumstances,

the smaller wheel slips on the rail so as to alter the normal diil'erence in the rates of rotation of the wheels, a dierence in the rates of rotation between the wheels equivalent to approximately at the circumference of a thirty-three inch wheel will cause the brush 64 to move from engagement with one contact strip 6I) or 6I into engagement with the other contact strip in approximately .242 second. and in proportionately less time as .10

the difference in rates of rotation increases.

From the foregoing it will be apparent that wherever' the difference in the rates of rotation between wheels as FW and RW is such that the brush 94 moves from engagement4 with one cona speed of nine and three-quarters miles per hourH 5.

tact strip 60 or. 6I into engagement with the Y other strip in less than .242 second, when the relays SRI and SR2 have a release time of .242 second. then a control operation is initiated. In the present instance the control operation en'- tails energization of the windings 3I and 33 with the lresult that the check valve 291s closed and the vent valve 30 is opened. In the course of a braking operation iluid under pressure is supplied 2'5 through the pipe 'P to the cylinder C so long as the check valve 29 is open. Thus when in the course of a braking operation the check valve'29 is closed and vent valve 30 is opened the cylinder C is disconnected from the source of iluld under pressure by the closing of the valve 29 and is vented to the atmosphere, in the present instance, by the opening of the valve 30, this venting resulting in reduction of pressure in thecylinder and effecting release ofthe braking means. 35

Of course, the arrangement could be such as to. reduce the e'ectiveness of the braking means, rather than release thereof, if this were desired. A's soon as the bra-king means are released or reduced in effectiveness the retarding force effective on the wheels is removed or reduced, as the case may be, and thereupon the wheels'tendk to resume normal rolling along the rails. When the wheels resume normal rolling along the rails the difference in the rates of rotation therebeof the contact strips in .242 second or less and therefore the switches of which -the armatures tween becomes such that the brush 64 no lon/ger 5 3l and 40 are a. part do not remain closedwith 50 the result that circuit to the windings 3I and 33 is broken and thereupon the ventv valve 30 closes and the check valve 29 opens. ,If the means operative to bring about the braking operation are still operating when this occurs, the braking means are again rendered eiective and if the retarding forces do not again Ybring about a difference in the rates of rotation of the wheels there will not be such movementof the Abrush 64 from engagement withone contact-strip 69 or 6I into engagement with the other contact strip that the windings 3| and 33 will be energized. If, however, re-applicationoi the braking, means again sets up a'difference in the rates of rotation between the Wheels as FW. and RW such that the brush 64 moves from engagement with one of the contact strips 60 or 6I into engagement with the other strip in .242 second or less,` the above described operation will be repeated.

It will be apparent from the foregoing4 that, since the slow-'t-release relays SRI and SR2A are simultaneously rendered operative by reason of a diierence in the rates of rotation of wheels as FW and RW, a control operation can be initiated prior to the time one of the wheels prematurely stops rolling and, therefore, where the control operation results in the release of the braking means, sliding of a wheel along a rail may be avoided for when the braking means are released (or reduced in effectiveness) the wheels, being freed of e. retarding force, resume normal rolling along the rail. f

In the form of my invention illustrated in Fig. 1, there may be such difference in the rates o! rotation of wheels as FW and RW that the brush B4 will move from engagement with 'one contact strip 60 or Bl into engagement with the other contact strip in or less than .242 second to there.. by render the relays SRI and SR2 operative simultaneously but the difference in the rates of rotation may be such thatl the brush 6l will not be freed from the second of the contact strips so engaged and move back into engagement with the first of the contact strips so engaged in .242 second. In such an instance the first of, the relays SRI or SR2 to be energized might release prior to the time the brush engaged the contact strip in circuit with this particular relay and' if this occurred circuit to the windings 3l and 33 would be broken. In a circumstance such as this, a condition might arise where the differencel in the rates of rotation of the rotors I5" and I6 would be such that the relays SRI and SR2 might be rendered operative simultaneouslyas the brush moved from engagement with one of the contact strips 69 or 6l into engagement with the other of the contact strips but such simultaneous operativeness of the relays would not be maintained until the brush moved from the second of thestrips so engaged back into engagement with the first of the strips so engaged. It will be apparent that if conditions ysuch as this arose, circuit would be alternately closed and opened through the windings 3l and 33vwith the result that the valves 29 and-30 would both be rendered operative and then inoperative, alternately, which is to say, a control operation would be alternately initiated and interrupted.

In order to avoid such alternate initiation and interruption of a control operation, my novel apparatus may be arranged in the manner illustrated in Fig. 5 wherein rotors similar to the rotors l5 and I6 in a switch Sa are respectively connected to wheels FWa and RWa through flexible shafts 23a and 26a, the switch Sa and the ilexibie shafts 23a and 29a being similar to the switch S and the flexible shafts 23 and 26 and being adapted for operation in a similar manner. Furthermore, slow-to-release relays SRIa and SR2a, similar to relays SRI and SR2, are provided as well as a source of current as the battery Bla.

`In this4 instance a conductor 42a leads from the source of current Bla to a terminal 43a and a conductor a leads from the terminal 43a to one end of the winding 45a of the slow-to-release relay SR2a. Another conductor 46a leads from the terminal 43a to one end of the winding 41a of the slow-to-release relay SRIa.

As in the case oi.' the switch S, a brush in the switch Sa, corresponding to the brush El. is connected to the source of current Bla through a conductor 48a while a contact strip in the lswitch Sa, corresponding to the contact strip 60, is connected to a conductor 59a which leads to the end of the winding 41a opposite to that to which the conductor 46a is connected. Further, a contact strip in the switch Sa, corresponding to the contact strip 6l is connected to a conductor 52a which leads to the end of the winding 45a mature 40a and'a contact 39a and the slow-torelease relay SRla includes an armature 31a and a contact 36a. A conductor 66 interconnects a contact 39a and the armature 31a. The armature 40a is grounded as indicated at Ila.

In the form of the invention shown in Fig. 5 a third slow-to-release relay SR3 is provided which includes a winding 61, one end of which is connected to a source of current as the battery B24 through a conductor 68, said source of current being grounded at 69. The other end of said winding 61 is connected to the contact 36a through a conductor 1li. The relay SRS includes an armature 1l that is grounded as indicated at 12 and this relay also includes a contact 13 engageable by the armature 1l upon energization of the relay SR3.

A solenoid 14 is provided to control operation of the combined check and vent valve 15 provided in the pipe `Pa through which fluid under pressure is supplied to the brake cylinder Ca which corresponds to the brake cylinder C. Upon energization of the solenoid 'I4 the valve 15 is operated to shut off supply of iiuid under pressure to the brake cylinder Ca and to vent said cylinder, the valve 15 therefore performing the function of the valves 29 and 30 shown in Fig. l.

The solenoid 14 includes a winding 16, one end of which is connected through a conductor 11 to a source of current such as the battery B3 that` is grounded as indicated at 18. A conductor 19 interconnects the other end of the winding 16 to the contact 13.

` In the form of the invention shown in Fig. 5 when a brush in the switch Sa, corresponding to the brush 64, rests on a contact strip in the switch Sa, corresponding to the contact strip B0, circuit is closed from the source of current Bla through conductor 49a and through the switch Sa, in thevmanner described in the description of the switch S, to a conductor 50a and through winding 41a and conductors 46a and 42a back to the source of current Bla whereupon the slow-torelease relay SRla is energized. When, however. a. brush in the switch Sa, corresponding to the brush 64, engages a contact strip in the switch Sa, corresponding to the contact strip 6l, circuit is closed from the source of current Bla through conductor 48a and through the switch Sa, in the manner described, to conductor 52a and through the winding 45a and conductors 44a and 42a hack to the source of current Bla whereupon the slowl-to-release relay SR2a is energized.

Energization of the relay SRla attracts the armature 31a thereof which thereupon engages the contact 36a, this armature remaining in engagement with this contact after circuit to the winding 41a is broken for a predetermined time inasmuch as the relay SRla is a s1owtorelease relay. Thus the armature 31a engages the contact 39a so long as the relay SRla is` operative.

`Likewise energization of the slow-to-release relay SR2a attracts the armature 40a which thereupon engages the contact 39a, and this armature 40a remains in engagement with this contact after,

contact 39a so long as the relay SRM is operative.

It will be noted that engagement of the armature 31a with'the contact 38a in the absence of the engagement of the armature alla with the contact 39a does not close circuit from ground lla through amature 40a, contact 39a, conductor 6B, armature Sla, contact 36a, conductor 10, winding 61, conductor 68, battery B2 to ground 68 to eect energization of the slow-to-release relay SRS. Furthermore, the engagement of the contact 40a with the contact 39a in the absence of the en'- gagement oi' the armature 31a with the contact 36a likewise does not close the just described circuit to eect en/ergization of the slow-to-release relay SRS.

When, however, a brush in the switch Sa, corresponding to the brush 84, moves from engagement with one of the contact strips in the switch Sa, corresponding to the contact strips 60 and 6 l, and engages the other contact strip during the time the slow-to-release relay energized by the engagement of said brush with the rst of said con tact strips still has the armature thereof engaged with the cooperating contact and the relay enf ergized by engagement of said brush with the second of the contact strips has attracted its armature into engagement with its cooperating contact, then the armature 40a. will be engaging thev contact 39a and the armature 31a will be engaging the contact SSa wherefore circuit to the winding 61 is closed and thereupon.slow-to-release relay SRS energizes.

The slow-to-release relay SRS has a release time sumclently prolonged that whenever this relay is energized it remains operative for a period suilicient to insure a control operation of not less than a. predetermined period of time. Thus where, as in the present instance, the slow-to-release relay SRS is arranged to control the supply of fluid under pressure to a brake cylinder as Ca, energization of this slow-to-release relay will initiate release of the braking means of Which the cylinder Ca is a part (or will reduce the effectiveness of such braking means) and will maintain this braking means released (or reduced in effectiveness) for not less than a predetermined period of time irrespective of how long the armatures 31a and lila remain in engagement with their cooperating contacts, this being due to the fact that energization of the sloW-to-release relay SRS initiates an operation which is not interrupted until release of the slow-to-release relay SRS. If the circuit is closed to the winding S1 of the relay .SR2 for but a short time the operation under control of the relay SRS will proceed for a period of time equal to the time of relatively brief energization of the winding 61 plus release' time of the relay SRS, and since the energization will be relatively brief the control operation will proceed for substantially the period of time repre-l sented by the release time of the relay SRS. In any event, however, the control operation will proceed for a period of time equal to the period for which the winding $1 is energized plus the release time of the relay SRS.

Therefore, by providing the relay SRS with a release time sufciently prolonged that a control operation of not less than a predetermined period will proceed each time the relay SRS is energized it is possible to avoid objectionable alternate initiation and interruption of a control operation such as might result from the utilization of an arrangement. 'such as shownin Fig. 1. Thus where the control operation is the release (or reduction in effectiveness) of the braking means of railway equipment, objectionable alternate release and application of the braking means will be avoided. Of course, even in this arrangement alternate release and application of the braking means might occur under a condition where the winding 81 was only momentarily energized and where, at the expiration of the release time of the relay SR2, both the armatures 31a and 40a would not be engaging their cooperating contacts, but wherein suchv engagement of the armatures would be eiected shortly after release of the relay SRS which would again result in energize.-

' tion of the relay SRS and which would of course A1S, conductor 19, winding 1B, conductor 11, battery BS to ground at 18, which energizes the solenoid 14 and operates the valve 15 to close oil the supply of iluid' under pressure to the brake cylinder Ca and vent this cylinder yto the atmosphere.

It has been explained heretofore that there may be relative movement between rotors as I5 and I6 even in normal operation of railway equipment and it has also been explained that Whenever a brush such as the. brush 64 is in engagement with a contact strip as the contact strips 6G and Si the sloW-to-release relay in circuit with the contact strip so engaged by the brush will bevenergized. However, where my novel apparatus is employed to prevent wheel sliding in the course of a braking'operation by either releasing the braking means operative during such a braking operation or reducing the retarding forces established by operation of the braking means, the device`may be arranged to prevent energization of the slow-to-release relays except during a braking operation by providing a control device such as the switch Sii, Fig." 8. In the present instance the switch Sli is pressureresponsive and is connected to the pipe Par. through a pipe 8i ahead of the valve 15 so that so long as there is fluid under pressure in the pipe Pa (which condition will prevail so long as a braking operation is in progress) the switch Si! will be closed. The switch 80, as shown, may be conveniently arranged in the conductors 5ta and 52a. to thereby disconnect spring contacts,

as 58 and 5S from relays as SRla and SR2a so long as the switch S was opened, which condition would prevail until fluid under pressure was supplied through the pipe Pa to the brake cylinder Ca during a braking operation. Hence, the relays as SRia and SR2a could only be energized when a braking operation was in progress which, in the present arrangement,l is the only time such relays need be energized.

'Ihere might also be conditions Where it would be desirable to interrupt relative rotation between rotors as I and i6, except when these rotors were to be utilized to effect a control operation, as where the control operation brought about -by predetermined operation of the rotors I5 and I6 relative to each other is the lrelease of braking means or the reduction of the retarding force established by operation of such means, the rotors would be rendered operative only when a braking operation is in progress. To this end a fluid-responsive clutch 82 would be interposed between the iiexible shaft as 23a and a shaft corresponding to the shaft 22, and another fluidresponsive clutch 83 would be interposed between the flexible shaft as 28a and the shaft as I8. A pipe as 84 connected to the pipe Pa ahead of the valve 15 leads to the clutch 82 through a branch pipe 85 and to the clutch 88 through a branch pipe 88 so that whenever fluid under pressure is supplied to the brake cylinder as Ca through a pipe as Pa the clutches 82 and 8l are engaged to thereby connect a rotor as I5 with a iiexible shaft as 23a and a rotor as I8 with a flexible shaft as 28a.

As will be apparent to those skilled in the art, a switch such as the switch 80 may be employed with or without clutches as 82 and 88 and likewise clutches as 82 and 83 could be employed with or without a switch as 8D, the use of these devices being dictated by the conditions under which my novel apparatus is used.

A further modified form of my invention is shown in Fig. 6 and herein a switch Sb is provided which is similar to the switch S and which includes rotors that in the present instance may be operated at rates proportionate to the rates of rotation of wheels of railway equipment lthrough flexible shafts as 23b and 28h that correspond to the shafts 23 and 28.

A source of current Bib is provided and a conductor 48h leads from this source of current to a terminal in the switch Sb corresponding to the terminal 49 in the switch S. Conductors Elib and B2b respectively lead from terminals in the switch Sb corresponding to the terminals 5| and 53 in the switch S. The conductor 50h leads to a terminal 81 while the conductor 52h leads to a terminal 88. Three slow-to-release relays SRlb, SR2b and SR3b are provided.

A conductor 42h leads from the source of current as the batteryBlb to a terminal 43h and a conductor 46b leads from the terminal 43h to one end of the winding 41b of slow-to-release relay SRIb, a conductor 89 connecting the other end of this winding to the terminal 81. A conductor 99 leads from terminal 43b to a terminal 8| and a conductor 44h leads from the terminal 8| to one end of the winding 45b of th slow-to-release relay SRZb, a conductor 92 leading from the other end of this Winding to the terminal 88. A conductor |32 interconnects the armature 31b with the terminal 89. A conductor 93 leads from the contact 38h to a terminal 94. A conductor 95 interconnects the armature 40D with the terminal 91 while a conductor 96 interconnects the contact`39b with the terminal 94. A conductor 10b leads from the terminal 94 to one end of the Winding 61b of the slow-to-release relay SR3b and a conductor 68D leads from the other end of this winding to the terminal 9|. The armature 1lb of the relay SR3b is grounded as indicated at 12b while the contact 13b is con nected through a conductor 19h to one end of the winding 1Gb of a solenoid 14b, the other end of this winding being connected through a conductor 11b to a source of current as the battery B3b which is grounded as at 18b.

So long as the slow-to-release relays SRib, SRZb and ERSU are operative the armatures 31h, 4Gb and 1lb are respectively engaged with the contacts 36h, 39h and 13b.l

In the switch Sb there is a brush similar to the brush 84 and contact strips similar to the contact strips 60 and 8|. When this brush engages a contact strip similar to the contact strip 80 circuit is closed from the conductor 48b to the conductor Elib and when this brush engages` a contact 4strip similar to Vthe contact strip 8| circuit is closed from the conductor 48h to the conductor l2b.

When circuit is closed from the source of current as the battery B|b through conductor 48h, switch Sb, conductor 89h to terminal 81, and through conductor 89, winding 41b and conductors 4Gb and 42h back to the source of current Bib, the slow-to-release relay SRib is energized and the armature 31h thereof is engaged with the contact 38h. In normal'operation this does not close circuit to the winding 81h since circuit to the conductor B2b is not closed at the same time circuit to the conductor 50h is closed and, therefore, the engagement of the armature 31o with the contact 38h does not close circuit from terminal 88 through conductor |32, armature 31h, contact 38h, conductor 83 to terminal 94. While closing of circuit to conductor 59h also closes circuit to conductor 85, circuit is not closed through armature 40h, contact 39h and conductor 96 to terminal 94 unless relay SRZb is operative to engage armature 4||b with contact 39h.

When circuit is closed to conductor 52h, it is also closed to terminal 88 and in normal opera- 'tion this does not close circuit through con ductor |32, armature 31b, contact 36h and conductor 93 to terminal 94 for at this time armature 31b will be disengaged from contact 38h. However, closing of circuit to conductor'52b also closes circuit to conductor 92 and through winding 45h, conductors 44h, 80 and 42h, circuit is closed back to the source of current Bib whereupon the winding 45h of relaySRZb is energized and the armature 40D is engaged with the contact 39h.

In the operation of the device when the brush in the switch Sb corresponding to the brush 84 in the switch S moves from engagement with one contact strip in the switch Sb, similar to one of the contact strips 60 or 6|, into engagement with the other contact strip in the switch Sb, similar to the contact strips 69 or 8|, as the case may be, in a period of time such that the slowto-release relay in circuit with the first of the so' engaged strips is still operative at the time the brush engages the other of the contact strips, circuit will be closed to the terminal 94.

Thus, if the slow-to-release relay SRlb were the iirst of the two relays to be energized and is the one which remains operative, then the armature 31h thereof is engaging the contact 86h whereforewhen the brush engages the one of the contact strips that closes circuit to conductor 52h, circuit will be closed from terminal 88 through conductor |32, armature 31h, contact 36h and conductor 98 to terminal 94. At this `same time the winding 45b will be energized to engage the armature 40b with the contact 39h and if, therefore, the brush similar to the brush 84 moves from engagement with the second of the contact strips to be engaged into engagement with the first of the contact strips to be engaged prior to the time the relay SR2b releases, iiow of current to the terminal 94 will be established from terminal 81, through conductor 95, armature 40h, contact 39h and conductor 86.

In either event it will be noted that when both the slow-to-release relays SRlb and SRZb are operative circuit is closed to the terminal 94 from the source of current Blb through conductor 48h and switch Sb and either through conductor 50h, terminal 81, conductor 95, armature 40b, contact 39h and conductor 96 or 70 time, then circuit thereto is broken.

90 and 02bback to the source of..cun'ent BIb whereupon vthe slow-to-release relay SRIb is rendered operative to attract its armature 'IIb into\ engagement with the contact '13b whereupon circuit is closed through the winding 'lsb l0 of the solenoid Mb from ground at 12b through armature "Hb, contact 13b, conductor 19h, winding b and conductor 11b to the source` of current as the battery B3b and to ground at 18h. This energizes the Winding of the solenoid 'Mb which may be arranged to operate a combined vent and` check valve similar to the combined vent and check valve 15, Fig. 5, and thereafter a. control operation will proceed in the manner described in connection with the description of Fig. 5.

The arrangement shown in Fig. 6 is quite similar to that shown in Fig. 5 but has an advantage over the arrangement shown in Fig. 5

in that the relay SR3b starts to energize as soon as a brush similar to the brush 64 engages a second contact strip, while the slow-to-release relay energized by engagement of the brush with the rst of the strips is still operative, whereas in the arrangement shown in Fig. 5

3|) it is necessary that the relay in circuit with fthe second of the ystrips so engaged be energized before circuit to sloW-to-release relay SRS is closed. In other respects the arrangements shown in Figs. 5 and 6 operate in an identical manner.

` the conductor 10c, Fig. '7, would lead from a contact corresponding to the contact 30a to winding tlc and through conductor 08e and battery B2b to ground at 69e. Ii used with the arrangement `shown in Fig. 6, the conductor 70e would lead from a terminal corresponding to the terminal 90, Fig. 6, through winding 61e, conductor 08o and the conductor shown in broken lines and indicated by c in Fig. 7 to a terminal corresponding to the terminal 0| and in s this instance conductor 60e would not be connected to a source ci current as B2C as shown in full line in Fig. 7. Thus in the arrangement shown in'Fig. 'l the slow-to-release relay 5R32; is energized Whenever an abnormal condition existsl and the energization of this relay engages the armature "i |c with the contact 73e to ground the conductor |0i.

In the present instance the conductor |0| leads to a terminal 91 and when conductor |0| is grounded circuit is closed through a conductor 00, armature 09, contact |00, conductor 10c, winding 76e, conductor Tlc, through the source of current Bac to ground at 18e. The winding 10c is part of a solenoid 'Mc which corresponds to, is

for the same purpose as, and operates in the same manner as the solenoids 'I4 and 14h.

If in the operation of the arrangement shown in Fig. '7 the solenoid 14e is maintained operative for more than a predetermined period of The predetermined period oi' time for which the sole.- noid 'Hc may continue to be operative will be of sufficient length to enable an intended control operation to be completed. Such a control 75 operation, as explained above, may be release oi braking means or a reduction in the eifectiveness oi!` such means. When. however. operation of the solenoid 'Mc is not interrupted at the end of such predetermined period of time. the control operation should nevertheless be interrupted- 4 because this will be indicative oi' an inadvertent and improper condition. To this end a slowto-energize relay SEI is provided and the aforesaid armature 00 and contact |00 are a part of this relay.

. l0 The slow-to-release relay SEI includes a winding |02, one end yof which is connected to the terminal Sl'throu'gh a conductor |00, the other end of this winding being connected to a source of current as the battery B4 through a conductor |04, said battery being grounded at 105. The

slow-to-energize relay ,SEI is such that the armature 90 thereof is not attracted from engagement with the contact |00 into engagement with the contact |00 until a predetermined time after circuit to the winding I02 of; this relay has been closed by the engagement 4oi.' armature 1|c with contact 73e.

Thus when the armature IIc is engaged with the contact '|3c to apply ground on the winding 10c and thereby render the solenoid 14c operative, circuit is also closed from ground at 12e through armature llc, contact 13e, conductor |0|, terminal 9i' and thence through conductor |03, winding |02 and conductor |04 to battery B0 and ground at |05. This energizes winding 102 but the armature 99 of the relay SEI is not attracted until circuit has been closed through the winding 02'for a predetermined time. When, however, circuit remains closed through the windf ing |02 for a predetermined period of time, the armature 00 is attracted from engagement with the contact |00 into engagement with the contact |06 and thereupon circuit -is closed from ground at |05 through the source of current B4, conductor |00, winding |02, conductor |03, ter minal S7, conductor 08, armature 99, contact |00, conductor |07 to xed'contact |08 and through movable contact I 00 to ground at |I0 whereby a stick or'holding circuit is closed through winding 102 to maintain the relay SEI energized.

Such disengagement of armature 90 from contact |00 breaks circuit to winding 16e wherefore the solenoid Ide is rendered inoperative. The solenoid 'itc will remain inoperative andl no further control operations will be effected until the stick circuit through winding |02 is broken.

' This stick circuit can only be broken by manually dissengaging the movable contact |00 from the ixed contact |08 and this'will not be-done until the reason vWhy circuit remained closed to the winding 16e for greater than -a predetermined period of time has been ascertained. Thus by the arrangement shown in Fig. 7 my device may be rendered inoperative until manually rendered operative and this Awill occur whenever a control operation is prolonged for greater than a predetermined period of time.

Obviously it will be advantageous to indicate the disengagementof the armature 99 from the con-tact |00 and the engagement thereof with the contact |06. relay SEI is provided with another armature I| I that is adapted to engage the contact II2 simultaneously with the engagement of the armature 99 with the contact |06. The armature ||I is grounded as indicated at II3 and a conductor IM leads from the contact l I2 to a terminal H5. Thus circuit is closed to terminal I|5 each time a stick circuit is closed for relay SEI.

Hence the slow-to-energize4 A circuit from ground is closed 'from the terminal through conductor H6, a visible signal such as the lamp L and conductor to a source of current las the battery B5 each time terminal ||5 is grounded by the engagement of armature with contact H2, said source of current B5 being grounded at H8. A conductor Il! leads from the terminal Il! to an audible signal such as the buzzer N which is connected to a source of current as the battery B6 through a conductor |20, said battery being grounded as indicated at 12|. Thus the buzzer N is rendered operative each time terminal I |5 is grounded.

Thus the visible signal L and the audible signal N are rendered operative whenever the solenoid |4c is rendered inoperative by the disengagement of the armature 89 from the contact |00. While it may be advantageous to maintain both the audible signal N and the visible signal L operative once circuit thereto is closed. there may be circumstances where it will be desirable to interrupt circuit to one or 'the other or both of these signals and to this end a manually operable switch may be provided for this purpose, such a switch being indicated at |22 and being provided in the conductor IIS to enable the audible signal N to be rendered inoperative by the manual opening of this switch. Of course, a similar switch could be provided in the conductor IIE to render the visible signal L inoperative or such a switch could be provided in the conductor |4 so that both of the signals could be rendered inoperative, if desired.

The arrangement shown in Fig. B is similar to that shown in Fig. 6 except that the arrange# ment shown in Fig. 8 enables a single source of current to be utilized and adilerent type of switch is employed.

The switch shown in Fig. 8 includes a shaft lBd suitably journaled in the switch housing (not shown) and this shaft is to be connected to a flexible shaft or the like corresponding to the flexible shaft 26. A shaft |`|d is also provided and which is also to be iournaled in suitable bearings in the switch housing and a flexible shaft similar to the flexible shaft 23 is to be connected thereto. The exible shafts used with the shafts l`|d andld, Fig. 8, are to be arranged, for example, to cause these shafts to rotate at rates proportionate to the rates of rotation of, and in the same direction as, different wheels of railway equipment or the like, although these shafts need not necessarily rotate in the same directions as the Wheels. Y

In this switch a conductive disc |23 is mounted on the shaft |8d but insulated therefrom and stationary spring contacts |24 engage this disc. Conductive discs |25 and |26 are mounted on but insulated from the shaft I'Id, and stationary contacts |21 and |28 respectively engage the discs |25 and |26. A plate |29 of insulating material is also fast on the shaft |`|d and carries contact strips 60d and Bld spaced from each other and of an extent similar to the contact strips 6|) and 6|. A spring contact 64d is carried by the bracket |30, fast on the shaft id, and this spring Contact is adapted to successively engage the strips 60d and Gld in a manner similar to that in which the brush 64 engages the contact strips 60 and 6I. 'I'he spring contact 64d is connected to the disc |23 through a conductor |3l. The contact strips 60d are connected to the disc |26 through a conductor 62d while the contact strips Sid are connected to the disc |25 through a conductor 63d.

these shafts is such that the spring contacts 64d do not disengage one of the contact strips 60d or Bid and engage the other of the contact strips in a time equal to or less than the release time of the slow-to-release relays SRld and SRM, the slow-to-release relays SRld and SE2d are not operative simultaneously, wherefore circuit is not closed tov the Yslow-to-release relay SRld. When, however, the spring contact 64d disengages one contact strip 60d or Bid and engages the other contact strip prior to the release of the slow-to-release relay energized by the engagement of the spring contact with the ilrst of such strips, then circuit is closed to the slow-torelease relay SRd.

Assuming that the spring contact 64d is engaging contact strip 60d, as shown in Fig. 8. then circuit is closed from the source of current Bld through conductor |34 to terminal |33 and from there through conducton 48d to spring contact |24 and thence through disc |23, conductor |3|, spring contact 64d, contact strips Sd, conductor 62d, disc |26, spring contacts |28 and conductor 50d to terminal 81d. From terminal 81d circuit is closed through conductor 89d, winding 41a', and conductors 46d and 42d back to the source of current Bld whereupon slow-to-release relay SRId is rendered operative to engage the armature 31d thereof with contact 36d. This, however, does not close circuit to the winding 61d of slow-to-release relay SR3d since circuit to conductor 52d is not closed at this time. Circuit is also closed from terminal 81d through conductor 85d to armature 40d which, however, at this time is disengaged from contact 39d wherefore circuit is not closed to the winding 61d. f

If, however, the spring contact 64d moves from engagement withy the contact strip Sd into engagement with the contact strip 6 id prior to the time slow-to-release relay SRid has released its armature 31d, then circuit is closed from the source of current Bld through conductors |34 and 48d, spring contact |24, disc |23, conductor |3|, spring contact 64d, contact strip Gld, conductor 63d, disc |25, spring contacts |21 and conductor 52d to terminal 88d. From terminal 88d circuit is closed through conductor |3211, armature 31d, contact 36d, conductor 93d to terminal 94d. Circuit is also closed at this time from terminal 88d through conductor 92d, winding 45d and conductors 44d, 90d and 42d back tothe source of current Bid wherefore the winding 45d of relay SRM is energized. If, therefore, the spring contact 64d moves from engagement with the contact strip 6 Id into engagement with the contact strip 60d prior to the time relay SE2d has released its armature 40d, circuit will be closed from terminal 81d (to which circuit will be closed in the manner above described) through conductor 95d, armature 40d, contact 39d and conductor 96d to terminal 94d.

In either event when circuit is closed to terminal 84d, winding 61d is energized, current ilowing from terminal 94d, through conductor d, winding 61d and conductors 68d, |35, 90d and 42d back to the source of current Bld whereupon slow-to-release relay SR3d is energized.

Slow-to-release relay SR3d is similar to and operates in the same manner as slow-to-release aesa'zcse g A cam member |38 is slidably but non-rotatrelay SR3 and when energized attracts its armature 1|d into engagement with contact 13d whereupon circuit is closed from the source of current Bld through conductor |34, terminal |33, conductor 12d,`armature 18d, contact-13d, conductor 11d, Winding 18d and conductors 19d, |38, 80d and 42d back to the source of current Bld. This renders solenoid 14d operative and this solenoid operates in the manner above described with reference to solenoid 14 to operate a valve s lmilar to the valve 15 for the purpose and in the manner above` described.

Al modification of the form of the invention shown in Fig. 8 is illustrated in Fig. 10, the difference between Figs. 8 and 10 residing in the form of switch eJmployed.

In the form of the invention shown in Fig. 10, shafts l1e and l8e are suitably Journaled in bearings in the switch housing (not shown) and ilexible shafts, corresponding to the flexible shafts 23 and 28, are connected to the shafts l1e and l8e so that they may be rotated at rates proportionate to the rates of rotation of, and in the same direction as, the wheels of railway equipment or the like although, here again, the shafts need not rotate in the same directions as the wheels.' The shaft l8e, however, carriesa substantially cup-shaped member |30e of insulating material and contact strips 80e and 8le are mounted on the inner periphery of the member |30e, said strips being of a length similar to and being spaced similarly to the contact strips 80 and 6l in the switch S. A conductor 83e con nects the strip 8le with a disc l28e, similar to the disc |25 and on which the brush l21e bears. A conductor 82e interconnects the strip 80e with a disc |286, similar to .the disc |28 and, on which the'brush |28e bears. An annular body |29e, fast on the shaft |1e, is disposed Within the substantially cup-shaped member l30eand carries a brush 84e `that is urged outwardly by a spring |38 so that the brush will successively ride over the contact strips 80e and Gle upon relative ro"- tation between the shafts l1e and l8e. A conductor l3le interconnects the brush 84e with the disc l23e, similar to the disc |23, and on which the brush l28e bears.

The switch shown in Fig. 10 operates in a manner similar to that hereintofore described and could be used in place of any of the switches thus far described. If this were done, for example, insofar as Fig. 8 is concerned, the conductor 88e would lead to a terminal similar to the terminal |33, Fig. 8, while the conductors 50e and 52e would respectively lead lto terminals corresponding to the terminals 81d and' 88d, Fig. 8. It is obvious thatwith the switch shown in Fig. l0 connected in this manner it would operate similarly tothe switch shown in Fig. 8 to 'bring about a control operation-in the above described manner.

A further modified form cf my invention is shown in Fig.' 11 and herein a somewhat different circuit and a somewhat different switch are illustrated. The circuit shown could be used with any of the switches thus far described, and the switch shown herein could be used with any of the circuits thus far described. In the form of my invention shown in Fig. 1l, shafts llf and l8f are provided which in the manner previously described may be connected to the wheels of railway equipment to rotate at rates proportionate to the rates of rotation of such Wheels and in the same direction, if desired.

ably mounted on the shaft |8f while a cam member |38 is fast on'the shaft l1. The cam members |38 and |33 have complementary cam surfaces l40 and l4l and a spring |42, disposed about the shaft |8f between the cam member |38 and the collar |43 fast on this shaft, urges the cam surfaces |40 and I 4l 'into cooperating relation. When the cam surfaces are cooperating with each other in the manner shown in Fig. 11.

the cam member |38 permits the rider |31 to assume the position shown wherein the contact 84f.'

controlled by the rider |31, engages the contact 801. However, if the cam surfaces move relative to'each other so that the high portions of the cam surface |40 are opposite the high portions of- Blf through conductor l34f, terminal l33f, conductor 48f, contact 84j, contact 80j, conductor 50i, to armature 40f which at this time will be disengaged from contact 38f and hence circuit is not closed in this instance to any of the slowto-release relays SRU, 8R21 or SR3f.

When, however, the high portions of the cam surfaces |40 and l4l are cooperating with each other, circuit is closed from the source of current Blf :through conductor l34f, terminal |33f, conductor 48f, contact 84j, contact 8lf, conductor EZf to terminal 88 andY from terminal 88f through conductor 92! and winding 45f,/ back through conductors 44f and 42f=to the source of current Blf whereupon slow-to-release relay SRZf is energized and the armature 40j is engaged with the contact 39f. This. however, does not close circuit to the winding 41f if the high portions of the cam surfaces |40 and. l4| are still opposite each other.

If, however, the relative rotation between the shafts l1f and l8f is such that immediately after the-high portions of the cam surfaces |40 and l4l have been aligned with each other, the cam surfaces move into relationship shown in Fig. 11, then the contact 84,f engages the contact 8llf and thereupon circuit is closed from the source of current Blf through conductor l34f, terminal l33f, conductor 481', contact 84], contact 8'0f, conductor 50i to armature 40f. If the contact 84f engagedthe contact 80f prior to the time the slow-to-release relay SRZf has released the armature 50f from the contact 39j, then circuit is closed through conductor 68f, winding 41f, and conductors 48f,'90f, and 42f back to fthe source of current Blf whereupon slow-to-release relay SRlf is energized and armature 31j thereof is engaged with contact 381.

Hence, if the relative rotation between the shafts |1f and l8f continues and the high por- 

